“Unveiling the Ingenious Visionary of Ancient Greece: A Forgotten Titan Who Redefined Innovation”
Heron’s known scientific works, meanwhile, include On the Dioptra, in which he describes a sophisticated surveying instrument very similar to a modern theodolite and methods for using it to determine overland distances; and Catoptrica, a treatise on optics whose principles of light propagation and reflection would only be improved upon 1,000 years by the Arab physicist Ibn Al-Haytham.
But Heron is by far best remembered for his mechanical innovations, as detailed in his remaining five books: Pneumatica, Automata, Mechanica, Cheirobalistra, and Belopoeica – the latter two dealing with catapults and other engines of war. Many of Heron’s inventions were created for use in Egyptian and Greek temples, producing seemingly miraculous special effects designed to enhance the perceived power and influence of the temple priests. One such device was a system for automatically opening and closing the temple doors when a fire was lit on a ceremonial altar. The mechanism consisted of a metal tank full of water hidden under the altar, connected to a siphon hose. This, in turn, drained into a bucket connected to a rope-and-pulley mechanism that operated the doors. When a fire was lit on the altar, the tank would heat up, forcing water out into the bucket, whose increased weight would slowly open the doors. And when, at the end of the ceremony, the fire was extinguished, the condensing and contracting steam inside the tank would create a suction that would draw water back out of the bucket, causing the doors to close. Heron also describes a pneumatic mechanism that automatically blew a trumpet whenever the doors opened. As outlandish as this mechanism may seem, it appears to actually have been implemented in many temples around the ancient world, for in Pneumatica, Heron states that:
“Some instead of water use quicksilver [Mercury] as it is heavier than water and easily disunited by fire.”
Though what exactly Heron meant by “disunited” is unknown, Mercury would indeed have allowed Heron’s door-opening mechanism to be made more compact and efficient, for it is denser and has a greater coefficient of thermal expansion than water. The element was long used in barometers and thermometers for the same reason. Unfortunately, no remains of Heron’s automatic door mechanism have ever been excavated, though given that later Christian and Muslim conquerers were known to have stripped ancient Egyptian and Greek temples of all available metal parts, this is hardly surprising.
